Refrigerator system



Sept, E949. D. E. MacLEOD LYUZI'YNWZ MEM Filed July l0. 1944 mm iff Patented Sept. 13, 1949 REFRIGEBATOB SYSTEM David Earle MacLeod, Evansville, Ind., assignor, by mesneassignments, to Seeger Refrigerator Company, a corporation of Minnesota.

Application July 10, 1944, Serial N0. 544,217

2 Claims. 1

simple, sturdy, emcient.y and which is adapted tov maintain two diil'erent levels of temperature in diierent chambers, each containing an evaporator connected in the same system.

Another object of the invention is the provision of an improved refrigerator system which may be utilized for providing household refrigeration at the normal temperatures for the preservation of food and freezing temperatures in another chamber for providing a freezing unit for the preservation of food by freezing it and maintaining it in a frozen'condition.

Another object of the invention is the provision of an improved refrigeration system f the class described which utilizes a minimum amount of apparatus and space, since a single condenser and a single motor compressor unitmay be utilized in the present system, with separate evaporators for producing two different temperature levels in different chambers.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawing, in which similar characters of reference indicate the same parts.

Referring to the drawing, the system shown includes a motor compressor unit I (motor not shown), and the compressor is illustrated with a housing II and rotor I2. Any type of motor compressor may be utilized capable of producing suitable pressure in suitable volume.

The compressor illustrated is of the eccentric rotor type. provided with a pair of blades I3, I4. The housing II is provided with a discharge port I5, which is located slightly in advance of the cut-off point, which is indicated by the axis I6-I6 and by the numeral I1.

The discharge port I is provided with a oneway valve I4 in the form of a resilient leaf valve, secured to the housing by the screw I9. This check valve I3 prevents the discharged gas from' flashing back into the compression chambers.

The housing I I is provided with two inlet ports, 20 the low pressure inlet port, and 2l the high pressure inlet port. The low pressure inlet port 20 communicates with an elongated slot' 22 for communicating with the chamber 23 in the housing beyond the vane I3 or I4.

The high pressure inlet port 2| may be provided with a relatively short slot 24 communicating with 2 the chamber 25 in the housing, which is in'tadvance of the blades I 3, I4. The direction of rotation is shown by meansv of the arrow 25.

The compressed gases pass out of the outlet port I5 into a suitable conduit 21 to a common condenser 28, which may be subjected to the action of a fan driven by the same motor, or to the cooling influence of air which is carried to the condenser and through it by convection.

The coils of the condenser 23 are connected by conduit 23 to conduits 30, 3|, which communicate with the evaporators 32, 33 through refrigerator controls 34, 3S. Any type of refrigerator control may be utilized at 34, 35, such as, for example, a thermostatically actuated valve which permits the refrigerant to pass whenever the temperature decreases below a certain predetermined amount and which closes when the temperature reaches a predetermined value.

The evaporator 32 is the high pressure evaporator, and itis connected by conduit 36 to a check valve 31 which communicates through conduit 3B tothe high pressure inlet port 2l. The check valve 31 may be of any desired type, but the ball type of check valve `is illustrated.

This check valve prevents the back-up of highpressure gas into the evaporator. The evaporator 33 communicates by means 0f vconduit y39 with check valve 40, which permits the ilow of-refrigerant into the compressor, but prevents the backup of the gas into the evaporator 33.

Check valve 4I) communicates by means of conduit 4I wth the low pressure inlet 20.

The mode of operation of the system is as follows:

The low pressure gas enters the port 20, and, after a blade, such as the blade I3, passes the end of the slot 22, it begins its compression movement. The other blade, such as I4, passes over slot 24 immediately thereafter, thus allowing high-pressure gas from port 2| to surge into the chamber back of blade I4 and in front of blade I3. The two charges of gas are then compressed and discharged through port I5, past valve I3, and into line 21 to the condenser. The check valve 31, in the line from the high-pressure evaporator 32, prevents back-up of the gas during the compression. The check valve 31 is shown remote from port 24 merely for purposes of illustration. In an actual design, the volume of the space between check valve 31 and the inlet port 24 would be made as small as practicable in order to keep re-expansion losses to a minimum.

Thecheck valves in the suction lines serve to prevent back-up of high pressure gas into the evaporators, and the discharge valve is used to prevent the discharged gas from flashing bac into the compression chamber.

The cycle is continued as the discharge gas llquefles in the condenser, whence the newly formed liquid passes through two different refrigerant controls to the evaporators. Gaseous refrigerant, under two different pressures, then returns to the compressor to complete the cycle.

The low pressure evaporator is preferably used for maintaining the temperature of the freezing unit, while the high pressure evaporator is preferably used for the normal cooling of the household refrigerator. i

Each of these hasits temperature controlle by a separate refrigerant control, but the system requires only one condenser and one motor compressor unit. The present system may operate at widely varying pressures and temperatures. For example, in one embodiment of the invention itis contemplated that the motor compressor outlet pressure will be about 150 pounds per square inch, while the inlet pressure from the high pressure evaporator may be at pounds per square inch, and the inlet pressure at the low pressure intake may be at 5 pounds per square inch.

With these pressures it is found that a freezing temperature can be maintained by means of a suitably adjusted refrigerant control 35 and a varying range of temperatures suitable for household refrigeration can be maintained by means of the evaporator 32, controlled at 34.

It will thus be observed that I have invented a new refrigeration system, in which only one motor compressor need be used, but two separate evaporators may be employed at different pressures and temperatures for household refrigeration and for freezing unit.

The present system is more economical than the devices of the prior art, in which separate evaporators and condensers, as well as motor compressors, were used for each system. By utilizing different pressures and intakes at different parts of the motor compressor, I am enabled to save the cost of an extra motor compressor and to combine the necessary condenser capacity in one single condenser, while still utilizing two separate evaporators controlled by separate refrigerant controls.

While I have illustrated a preferred embodiment of my invention, many modications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

l. In a refrigeration system, the combination of a rotary compressor having a housing provided with a substantially cylindrical chamber, an eccentric rotor located in said chamber, engaging the side walls of said chamber and engaging the periphery of said chamber at a cut-off point, said rotor being provided with a pair of slidably mounted vanes for engaging the periphery of the chamber and said chamber being provided; with a high pressure outlet, a low pressure inlet and an intermediate pressure inlet, said high Pressure outlet being located adjacent to and in advance of said cut-03 point with reference to the direction of rotation of the rotor, the low pressure inlet being located adjacent to and on the `opposite side of said cut-off point, and the intermediate pressure inlet being located between the said high pressure outlet and the low pressure inlet, whereby different suction pressures are produced at said low pressure inlet and said intermediate pressure inlet, the said outlet being connected to a condenser and said condenser being connected to a pair of conduits, each conduit lncluding restriction means and said conduits leading, to two separate evaporators, each evaporator being connected by a conduit to one of said inlets, whereby the two evaporators may be maintained at diierent suction pressures, and henceat different temperatures by a single compressor.

2. In a refrigeration system, the combination of a rotary compressor having a housing provided with a substantially cylindrical chamber, an eccentric rotor located in said chamber, engaging the side walls of said chamber and engaging the periphery of said chamber ,at a cut-off point, said rotor being provided witha pair of slidably mounted vanesfor engaging the periphery of the chamber and said chamber being provided with a high pressure outlet, a low pressure inlet and an intermediate pressure inlet, 'sa'id high pressure outlet being located adjacen'tto and in advance' of said cut-oil point with reference to the direction of rotation of the rotor, the low pressure inlet being located adjacent to and on the opposite side of 4said cut-off point, and .the intermediate pressure inlet being located .between the said high pressure outlet and the low-pressure inlet, whereby different suction pressures are produced at said low pressure inlet and said intermediate pressure inlet, the said outlet being connected to a condenser and said condenser being connected to a pair of conduits, each conduit including restriction means and said conduits leading to two separate evaporators, each evaporator being connected by a conduit to one of said inlets, whereby the two evaporators may be maintained at different suction pressures, and hence at different ltemperatures by a single compressor, the said restriction means comprising a separate temperature responsive restrictor valve for controlling the flow of refrigerant from the condenser into each evaporator, whereby the evaporators may be maintained at substantially constant temperature irrespective of the cooling load placed upon them.

DAVID EARLE MACLEOD.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Kucher May 27, 1941 

